1. Field of the Invention
This invention relates to an electromagnetic trigger device in a camera capable of effecting time exposure.
2. Description of the Prior Art
There has been proposed a motor-driven camera such as, for example, a cine camera which is provided with a member for stopping the shutter in a position in which the shutter is fully open (to be referred to as the open shutter position hereinafter) in order to attain a long exposure time required under the low or poor lighting condition such as exposure at night or the microscopic photography, and with a member for stopping the shutter in a position in which the shutter is completely closed (to be referred to as the closed shutter position hereinafter). The motor-driven camera of type described is disclosed in U.S. Pat. No. 3,721,492. However, in such camera, when a shutter release button is depressed to terminate a long time exposure, the shutter is closed and the next frame of film is transported and successively the next exposure is initiated.
This is inconvenient for long time exposures wherein the time intervals between exposures of adjacent frames of film may be such that a 20-second exposure of a frame is followed by a 5-minute interval which in turn is followed by 20-second exposure of a subsequent frame and then by a 5-minute interval, as in the microscopic photography of cell division, crystal growth or the like. Further, this camera has the advantage that when the shutter release button which is already depressed may be released to terminate continuous exposure the shutter is stopped in the shutter open position depending on the timing of the release of the button because of two shutter stop members.